1. Field of the Invention
The present invention relates to a communication system which performs communication between communication devices via a communication path and, more particularly, to communication path control.
2. Description of the Related Art
In a mobile communication system, a communication terminal such as a mobile telephone communicates with a base station so as to access the Internet via a core network. The communication terminal performs communication over a communication path (e.g., a bearer) established with a device (e.g., a gateway) installed in the core network.
When a communication path is established, a core-network node (e.g., a gateway) for relaying the communication path is assigned to this communication path. A communication path establishment procedure is described in Subchapter 5.3.2 of 3GPP TS 23.401 V12.1.0 “Technical Specification Group Services and System Aspects; General Packet Radio Service (GPRS) enhancement for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Access”, [retrieved on Aug. 26, 2013], the Internet <http://www.3gpp.org/ftp/Specs/html-info/23401.htm>.
As described above, a core-network node such as a gateway is assigned to an established communication path. Accordingly, when switching a communication path route, it is expected that a communication path reestablishment procedure is performed to reassign a core-network node to a new communication path. When the communication path reestablishment procedure is performed, it is expected that communication services are affected in various ways, such as, for example, interruption of communication that has been performed over a communication path before switching.